For a start, what if $a is a tied variable?

I added a "my". Now the compiler can determine that it isn't tied.

What happens to any benefits (which I seriously doubt exist) from maintaining cache coherency when it is sharing the cpu with say a browser charged with stretching or shrinking a .jpg that has been given badly chosen width/height attributes?

There are no browsers running on my servers. Moreover, I have control over everything that is running

Maintaining cache coherency can yield performance in processes that have uninterupted use of the processor, but in preemptive multitasking environnments those benefits derived by extremely laborious and careful hand coding or hugely complex analysis compilers are completely negated every 200ms (or similar) when the OS swaps tasks. Perl 5 has no way to realise such benefits.

In that 200ms, I may have served hundreds of requests. I'm quite willing to take an optimization that is useful on 99% of requests and doesn't hurt on the other 1%.

In reply to Re^7: order of arguments evaluated by kscaldef
in thread order of arguments evaluated by Anonymous Monk

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